What is Klinefelter's?

Question

What is Klinefelter's?

Answer 1

It's an additional X chromosome on the 23rd pair.  Instead of XY, with Klinefelter's they have XXY, or XXXY, or XXXXY, etc.

Answer 2

http://en.wikipedia.org/wiki/Klinefelter...

Answer 3

Klinefelter Syndrome

What is Klinefelter syndrome?

Klinefelter syndrome, also known as the XXY condition, is a term used to describe males who have an extra X chromosome in most of their cells. Instead of having the usual XY chromosome pattern that most males have, these men have an XXY pattern.

Klinefelter syndrome is named after Dr. Henry Klinefelter, who first described a group of symptoms found in some men with the extra X chromosome.  Even though all men with Klinefelter syndrome have the extra X chromosome, not every XXY male has all of those symptoms.

Because not every male with an XXY pattern has all the symptoms of Klinefelter syndrome, it is common to use the term XXY male to describe these men, or XXY condition to describe the symptoms.  

Scientists believe the XXY condition is one of the most common chromosome abnormalities in humans.  About one of every 500 males has an extra X chromosome, but many don’t have any symptoms.

For more information on genes and chromosomes, check out Cells 101.

What are the symptoms of the XXY condition?

Not all males with the condition have the same symptoms or to the same degree.  Symptoms depend on how many XXY cells a man has, how much testosterone is in his body, and his age when the condition is diagnosed.

The XXY condition can affect three main areas of development:

Physical development: As babies, many XXY males have weak muscles and reduced strength.  They may sit up, crawl, and walk later than other infants.  After about age four, XXY males tend to be taller and may have less muscle control and coordination than other boys their age.

As XXY males enter puberty, they often don’t make as much testosterone as other boys.  This can lead to a taller, less muscular body, less facial and body hair, and broader hips than other boys.  As teens, XXY males may have larger b*****s, weaker bones, and a lower energy level than other boys.

By adulthood, XXY males look similar to males without the condition, although they are often taller.  They are also more likely than other men to have certain health problems, such as autoimmune disorders, breast cancer, vein diseases, osteoporosis, and tooth decay.

XXY males can have normal s*x lives, but they usually make little or no sperm.  Between 95 percent and 99 percent of XXY males are infertile because their bodies don’t make a lot of sperm.

Language development: As boys, between 25 percent and 85 percent of XXY males have some kind of language problem, such as learning to talk late, trouble using language to express thoughts and needs, problems reading, and trouble processing what they hear.

As adults, XXY males may have a harder time doing work that involves reading and writing, but most hold jobs and have friends, families, and normal social relationships.